A beam deflecting arrangement of a vapor deposition system is sold by the Leybold Company under the product designation “MDC e-Vap-PSL Programmable Sweep Control”. In this beam deflecting arrangement it is possible to fix the course of the electron beam in advance of starting the vaporization process. This course is to be traveled by the electron beam during the subsequent operation of the vapor deposition system. In this context, it is possible to develop a pattern deviating from the courses of the electron beam deflection which are stored in the control of the vapor deposition system as a basic configuration. This pattern is subsequently traveled by the electron beam continuously in a repetitive manner.
It is, however, disadvantageous that the burn-off of the material to be vaporized is not optimal because of the periodic deflection of the electron beam. This burn-off is especially the largest at the center so that the crucible having the vaporization material must be exchanged prematurely which has a negative effect on cost because the material which is used is, as a rule, expensive and is, for example, gold. In addition, an unsymmetrical pear-shaped vapor cloud can occur.
The BOC Coating Technology Company markets a beam deflection system called a “Temescal Bipolar Sweep”. In this system, the deflection in both coordinate directions can be sinusoidally-shaped or triangularly-shaped (with an adjustable fixed amplitude and adjustable fixed offset). The two deflecting frequencies can be different or they can be the same. The beam deflection runs synchronously in both coordinate directions only when the frequencies are the same. There are eight preadjustable parameter sets (amplitude, frequency, offset, each for the X-direction and the Y-direction) between which a switchover can be made during the vapor deposition procedure.
With this apparatus too, the burn-off on the vaporization material can be only imprecisely controlled because the deflecting functions are fixed to the sine and cosine functions or to the triangular function. It is only possible to adjust offset, amplitude and frequency once for each coordinate direction.